feat(surround): support complex tags surround

[admosity]

Fixes issue with complex tag surround by only including the actual tag name instead of the whole contents of the tag.

Before:

After:

Couldn't find any tests written for surround... So no tests. If someone lets me know where I should put tests for this; I'll update the PR.

[xconverge]

let me add a few surround tests real quick, then you can add yours there! :)

[xconverge]

There you go, could you add one or two to test/plugins/surround.test.ts

Thanks!

[admosity]

Thanks! Updated.